Method for producing polymer particles by the polymerization of fluid drops in a gas phase

Abstract

A process for producing polymer particles by polymerizing liquid droplets in a gas phase by metering a liquid comprising at least one monomer from at least one feed by means of a multitude of bores into a reaction chamber comprising the gas phase, wherein ratio of length of the feed to greatest diameter of the feed in the region of the multitude of bores is at least 10.

The invention claimed is: 
     
       1. A process for producing polymer particles by polymerizing liquid droplets in a gas phase by metering a liquid comprising at least one monomer from at least one feed ( 1 ) by means of a multitude of bores into a reaction chamber comprising the gas phase, wherein a ratio of length of the feed ( 1 ) to greatest diameter of the feed ( 1 ) in a region of the multitude of bores is at least 10. 
     
     
       2. The process according to  claim 1 , wherein a plurality of feeds ( 1 ) lead radially into an upper part of the reaction chamber. 
     
     
       3. The process according to  claim 1 , wherein the multitude of bores is arranged in at least one row along the feed ( 1 ). 
     
     
       4. The process according to  claim 1 , wherein the multitude of bores is arranged in at least two rows offset with respect to one another along the feed ( 1 ). 
     
     
       5. The process according to  claim 1 , wherein the feed ( 1 ) is planar in the region of the bores. 
     
     
       6. The process according to  claim 1 , wherein the feed ( 1 ) has at least two rows of bores in a longitudinal direction and, in the region of the bores, two planar regions, each planar region having at least one row of bores and verticals to the two planar regions in the cross section of the feed ( 1 ) intersecting above the bores and forming an angle. 
     
     
       7. The process according to  claim 1 , wherein the bores have a diameter of from 50 to 1000 μm. 
     
     
       8. The process according to  claim 1 , wherein the a pressure in the feed line ( 1 ) is at least 0.1 bar. 
     
     
       9. The process according to  claim 1 , wherein the liquid passes into the feed ( 1 ) through a plurality of feeds ( 2 ). 
     
     
       10. The process according to  claim 9 , wherein the liquid passes into the feed ( 2 ) through a feed ( 3 ), and a second liquid comprising at least one initiator through a feed ( 4 ). 
     
     
       11. The process according to  claim 10 , wherein the feeds ( 2 ) comprise static mixers. 
     
     
       12. The process according to  claim 10 , wherein at least one of the feeds ( 1 ), ( 2 ), ( 3 ) and ( 4 ) is cooled and/or a separate gas stream flows around it. 
     
     
       13. The process according to  claim 1 , wherein gas with a temperature of from 90 to 300° C. is introduced from above into the reaction chamber by means of at least one gas feed ( 5 ) and the at least one gas feed ( 5 ) ends below the feed ( 1 ). 
     
     
       14. The process according to  claim 13 , wherein gas with a temperature of from 0 to 60° C. is introduced from above into the reaction chamber by means of at least one gas feed ( 6 ) and the at least one gas feed ( 6 ) ends above the feed ( 1 ). 
     
     
       15. The process according to  claim 12 , wherein the liquid is conveyed in circulation in at least one of the feeds ( 1 ), ( 3 ), and ( 4 ) partly via a cooler ( 8 ). 
     
     
       16. The process according to  claim 12 , wherein at least one of the feeds ( 1 ), ( 2 ), ( 3 ) and ( 4 ) has a cooling jacket ( 9 ), the cooling jacket ( 9 ) being interrupted in the region of the multitude of bores. 
     
     
       17. The process according to  claim 10 , wherein at least one of the feeds ( 1 ), ( 2 ), ( 3 ) and ( 4 ) is additionally thermally insulated. 
     
     
       18. The process according to  claim 10 , wherein at least one of the feeds ( 1 ), ( 2 ), ( 3 ) and ( 4 ) comprises a polymeric material. 
     
     
       19. The process according to  claim 1 , wherein the monomer is acrylic acid to an extent of at least 50 mol %. 
     
     
       20. The process according to  claim 1 , wherein the polymer particles have a centrifuge retention capacity of at least 15 g/g. 
     
     
       21. The process according to  claim 1 , wherein the feed ( 1 ) is cooled and/or a separate gas stream flows around it. 
     
     
       22. The process according to  claim 1 , wherein the feed ( 1 ) is additionally thermally insulated. 
     
     
       23. The process according to  claim 1 , wherein the feed ( 1 ) comprises a polymeric material.